Bomb Calorimeter

What is a Bomb Calorimeter?

The calorimeter used to determine the energy change during a reaction accurately is known as a bomb calorimeter. The modern Bomb calorimeter is a development of the original calorimeter of Berthelot. The modern bomb calorimeter is made of corrosion resisting steel in which the combination Bomb Calorimeter.

The bomb calorimeter is an instrument used to measure the heat of reaction at a fixed volume and the measured heat which is called the change of internal energy (ΔE). In chemistry, the changes of heat of a reaction can be measured at fixed pressure or volume.

Working of Bomb Calorimeter

The bomb calorimeter is a type of constant-volume calorimeter used to measure the combustion heat of oxygen-burnable samples. Four critical parts are needed in every bomb calorimeter.

The bomb calorimeter is a laboratory instrument used to measure the amount of a sample’s combustion heat or heat power when excess oxygen combustion occurs. The purpose of this research is to determine the effect of using the bomb calorimeter on the ability of physics students to process science. Influences involve the efficacy of using the devices and learning how to develop the abilities of the scientific method of students before and after using materials.

If the heat capacity of the calorimeter is known, then one can determine the heat change during a chemical reaction by noting the change in the temperature in the process.
The heat
Q = Cv(Tf –Ti)
where, q is the amount of heat according to the change in temperature measured in joules
Cv is the heat capacity of the calorimeter
Tf  is the final temperature
Ti is the initial temperature

Image of Bomb Calorimeter

Bomb Calorimeter

Construction of Bomb Calorimeter

The bomb calorimeter is used to determine the calorific values of solid and liquid fuels. It consists of a strong steel shell known as a bomb.

It consists of a base which supports the platinum crucible and is screwed to the body of the bomb. The top of the bomb carries an oxygen supply connection and a valve to release the product. One gram of powdered sample coal is taken for the test and the calorimeter is filled with 2000cm3 of water. The sample is placed in the platinum crucible. The iron fuse wire which surrounds the sample of coal, is connected to the lower end of the two electrodes. The electrodes extend through the base of the bomb and connect the fuse wire to an electric circuit. The coal can be ignited by closing the electric circuit.

The bomb is placed inside a copper vessel which contains water. There is a stirring device for agitating the water within the calorimeter. The calorimeter containing the bomb is placed in another container which acts as a heat insulator. The temperature of water in the calorimeter is measured by a thermometer.

The oxygen cylinder is coupled to the bomb and oxygen is admitted to the bomb through the value until the pressure gauge in the cylinder indicates a pressure of 25 atmospheres. The fuel is ignited by passing a current through the fuse wire. The temperature of both starts increasing and the readings on the thermometer are taken at one minute intervals for 10 minutes, after the maximum intervals for 10 minutes, after the maximum temperature is reached. Thereafter the temperature starts falling slowly. When the temperature fall shows a steady rate the readings are taken at regular intervals for an additional five minutes.

Heat given by the combustion of coal + Heat given by the combustion of fuse wire = Heat taken by the water and calorimeter.

Uses of Bomb Calorimeter

A bomb calorimeter is an instrument used to determine the heat emitted from a given quantity of biomass sample combustion and to calculate the HHV of that biomass fuel. Approximately one gramme of sample fuel is ground and diluted after each test to fit into a capsule for bomb combustion. The emitted heat increases the temperature of the water covering the bomb by combusting the fuel. The total heat of the fuel is determined by increasing the temperature and the real mass of the fuel.

In different industries and academic environments, calorimeters are helpful, and an industrial pilot plant may use a DSC to assess a shift in the formula of a substance and how it impacts the formula itself. To calculate the amount of heat (calories) in food, oxygen bomb calorimeters are useful in food testing laboratories.

Frequently Asked Questions on Bomb Calorimeter


What is the principle of bomb calorimeter?

Combustion Calorimeters calculate the heat that a combustible solid-liquid material emits. This is achieved by measuring into a crucible an exact amount of the sample material, putting the crucible inside a “bomb” (a enclosed metal container called a pipe), filling the oxygen pipe and igniting the material.


Why is a bomb calorimeter more accurate?

Much as for a coffee cup calorimeter, the temperature differential of the bomb vessel is measured. Our bomb vessel houses 8 high-precision temperature sensors within the walls of the bomb vessel, enabling quick and precise temperature measurement instantaneously.


What does a bomb calorimeter determine in a food sample?

A bomb calorimeter is used to measure, under controlled conditions, the heat emitted by a sample burned under an oxygen atmosphere in a closed vessel (bomb) surrounded by water. The consequence of the calculation is called the amount of combustion, calorification, or BTU.


How do we use a calorimeter?

In their science project tests, many students use calorimeters when they need to measure heat potential or the basic heat of a material. In general, a calorimeter is used to determine the sum of heat energy and then uses it to quantify the precise heat of a material or other details related to heat.


What are the necessary features of a calorimeter?

Basically, a bomb calorimeter consists of a small sample cup, oxygen, a stainless steel bomb, water, a stirrer, a thermometer, a dewar or an insulating bottle (to avoid heat transfer to the atmosphere from the calorimeter) and a bomb-connected ignition circuit.

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  1. Why is only hcv obtained from bomb calorimeter

    • A bomb calorimeter is used for finding the higher calorific value of solid and liquid fuels. Gross calorific value (G.C.V) or higher calorific value (H.C.V): It is total quantity of heat liberated when one unit of fuel is burnt completely and the product of combustion has been cooled to room temperature. It is also called higher calorific value (H.C.V).